This invention relates to vehicle-mounted crash attenuation systems.
Crash attenuation devices have been developed for mounting on vehicles that are parked or moving slowly on roadways, for example at construction or maintenance sites, in order to attenuate the impacts from collisions with the parked vehicle. Often times, vehicles equipped with crash attenuators are purposely deployed around work sites to shield workers at the site from being hit. Instead, errant vehicles strike the attenuator which arrests the motion of the vehicle and dissipating its impact energy. Examples of these attenuation devices are disclosed in U.S. Pat. Nos. 5,052,732, 4,635,981, and 4,658,941 incorporated herein by reference.
In order to accommodate impacts at highway speeds, attenuation devices need to be quite large. Because of the difficulty in operating vehicles with a large attenuation device extending from vehicle, these attenuation devices are often pivotally mounted on vehicles, so that they can be pivoted into a vertical position so that the vehicle can be more easily moved.,
While crash attenuation devices have proven to be valuable both in protecting workers at work sites and in protecting motorists, those presently available still have a number of problems. One such problem is that the attenuation devices are easily damaged, and repair or replacement of the damaged devices can be expensive. Many of these attenuation devices were subject to vibration damage from the movement of the vehicles onto which they were mounted. A further problem is that many of these devices are incapable of completely attenuating high speed impacts, and many do not come close to comply with the 65 mph impact standards (NCHRP-350) recently promulgated by the U.S. Department of Transportation.
The crash attenuation device of the present invention is adapted for mounting on a vehicle to attenuate the impacts from collisions. Generally, the attenuation device of the present invention comprises a frame adapted to be mounted on the vehicle, and a slider mounted on the frame to slide relative to the frame toward the vehicle in response to an impact. At least one collapsible, energy-absorbing member positioned between the slider and the frame to absorb energy as the slider telescopes relative to the frame. A crushable, energy-absorbing crash cushion is mounted on the outside side of the slider.
The crushable, energy-absorbing crash cushion is preferably pivotally mounted on the slider to pivot between a horizontal position deployed position in which the crash cushion extends horizontally to intercept impacts, and a vertical storage position in which the crash cushion extends generally vertically to facilitate movement of the vehicle. The crash cushion preferably comprises at least two sections of different energy absorption capability. Replaceable cartridges are preferably mounted on the back and rear sides of the crash cushion to absorb minor impacts without making the entire crash cushion unserviceable.
The crash attenuation device of the present invention arrests the motion of the impacting vehicle and dissipates its impact energy. The device is stable and resists damage induced from movement of the vehicle on which it is mounted. The device can be easily and simply repaired, rather than requiring replacement upon minor collisions. These and other features and advantages will be in part apparent, and part pointed out hereinafter.